The authors are grateful to Professor Yixin Yang from Northwestern Polytechnical University and the crew of the M/V Hupuyu 48920 for their help with the observations. Financial support for this research was provided by the National Natural Science Foundation of China (Grant No. 41576027) and the National Marine Public Welfare Research Project of China (Grant No. 201505027). We thank Dalia Lahav-Jones;
from Liwen Bianji;
Edanz Group China (www.liwenbianji.cn/ac);
for editing the English text of a draft of this manuscript;